This application is based on and claims priority from Japanese Patent Applications No. Hei 3-145599 filed May 21, 1991 and No. Hei 3-203483 filed Jul. 19, 1991, the disclosures of which are incorporated by reference herein.
The present invention relates to an optical element with an aspheric surface and a process for producing the same.
Optical elements with an aspheric surface such as aspheric lenses have been proposed for correcting the aberrations that will develop in spherical lenses and, hence, they are used as eyepieces and high photographic lenses. Lenses are manufactured from glass or plastics and in order to work glass to have an aspheric surface, grinding and polishing operations are necessary for each lens. Hence, aspheric glass lenses have the disadvantage of being unsuitable for large-scale production and having only limited consistency in the precision of lens machining. Under these circumstances, aspheric glass lenses find utility only in specialty optical elements. In contrast, aspheric plastic lenses can be shaped with molds and hence are highly suitable for large-scale production. However, they do not have high heat and dimensional stability and can only be used in applications that do not require very high precision.